(a) Field of the Invention
This invention relates to a wall and floor system for building construction and more particularly but not by limitation to a cold-formed steel structural wall and floor framing system used in commercial and residential buildings.
(b) Discussion of Prior Art
Now and in the past, cold formed steel, also referred to as light gauge steel, wall stud and floor joist framing has been used extensively, in particular for exterior curtain wall and interior non-bearing construction, primarily as replacement for wood stud framing used for partition walls and ceiling support framing in buildings where combustible materials are not permitted by building codes. More recently, cold formed steel bearing construction has been increasingly used as the structural load resisting elements for single and multi-story buildings, up to 9 or more stories.
Structural steel stud framing is manufactured in the United States using a minimum of 25% recycled steel, which is an advantage when considering the movement towards energy efficient construction and sustainable design. Further, steel stud framing and steel components are 100% recyclable upon a building's future demolition. Steel stud framing systems are straight and dimensionally accurate and consistent without material imperfections common in wood, concrete, and masonry, and can be manufactured to any required length during fabrication that is practical for shipping and erection.
Pre-assembled wall panels of studs and track can be shop fabricated and delivered to the construction site to be erected as pre-assembled units, saving construction time, labor, and on-site scrap and waste. Cold formed steel structures are lighter, more environmentally friendly, and take less skilled labor to construct than similar structures built using structural masonry, reinforced or pre-cast concrete bearing wall structures. A lighter structure has several advantages, such as lower weight for transportation costs, lighter and smaller foundations, and lower seismic forces, as seismic forces are directly proportional to building self weight. In high seismic areas, lower seismic forces further reduce cost of lateral frames, connections and collectors, as well as size and intricacy of foundations supporting lateral frames. Therefore, a lighter structure saves materials, labor, shipping, and complexity, creating a much more efficient structure and lower overall environmental impact than a heavier structure constructed with pre-cast floor planks, or masonry or concrete bearing walls.
Heretofore, there have been a large number of issued patents related to cold-formed, steel building structures, components, prefabricated assemblies and prefabricated structures. These patents disclose various structural components including the use of cold formed steel structural studs, track, joists and bridging, which have been used as standard construction materials for nearly 50 years.
The patents include U.S. Pat. No. 1,981,240 to Mcneil, U.S. Pat. No. 5,720,138 to Johnson, U.S. Pat. No. 5,274,973 to Liang, U.S. Pat. No. 5,647,186 to Donaldson, U.S. Pat. No. 6,519,911 to Sawada, U.S. Pat. No. 5,113,631 to diGirolamo et al., U.S. Pat. No. 4,716,695 to Alexander et al., U.S. Pat. No. 5,782,047 and U.S. Pat. No. 6,298,617 to De Quesada, U.S. Pat. No. 5,941,035 to Purse, U.S. Pat. No. 5,881,516 to Luedtke, U.S. Pat. No. 6,799,408 and U.S. Pat. No. 7,178,304 to Brady, D467,007 to Daudet et al., U.S. Pat. No. 4,075,810 to Zakrzewski et al., U.S. Pat. No. 4,130,970 to Cable, U.S. Pat. No. 4,161,087 to Levesque, Ser. No. 12/548,694 to Beck et al, Ser. No. 12/505,478 to Wing-Chow Siu, U.S. Pat. No. 5,479,749 to Colasanto et al, U.S. Pat. No. 5,412,919 to Pellock et al, and U.S. Pat. No. 7,739,850 to Daudet.
None of these prior art references disclose the unique combination of structure and features of the subject cold-formed steel structural wall and floor framing system. In particular, the above mentioned patents don't teach or suggest a system having top and bottom spanning tracks used to distribute point loads from wall studs and floor joists to offset supporting wall studs and floor joists indexed below.